Respuesta :
					                   10 is the answer. Factors of 10: 1, 2, 5, 10. 10 also goes into 40 so 10 is the GCF
					                
					                
					             
					                   The greates common factor is 10 because you are trying to find what number divides into 10 and 40 and 10 can go into 10 and 40.Hope it helped
					                
					                
					              
					                  